1. Field of the Invention
This invention relates generally to a multi-line recording device such as a telephone answering machine, and more specifically, to a recording device configured to concurrently record data from multiple sources.
2. Background
Modern communication systems often include means to detect and record incoming calls when the call recipient is not available to personally take the call. These types of devices, commonly known as answering machines, are generally considered to increase productivity and provide convenience. Modern answering machines also provide capability for remote dial-in by providing means for an operator to call the answering machine using a remote telephone and retrieve the stored messages.
Many new answering machines record messages digitally, that is, after converting the incoming voice signal into a digital signal. To reduce the amount of required memory, the digitized signal is compressed prior to storage in memory. A processor or other computing means performs the compression of the audio signal.
Furthermore, the increase in worldwide communications, telecommuting, teleconferencing, Internet access, and business operation from the home, has lead to an increase in the use of multiple telecommunication lines to a particular situs, such as the home or office. Multiple telecommunication lines increases productivity and adds convenience for individuals in need of multiple means of simultaneous or concurrent communication. Given the widespread use of answering devices and the growing popularity of two or more telephone lines, an answering device for two or more lines is desired.
Various attempts to provide automatic answering and remote call receipt via an answering device configured for two or more lines have been unsuccessful or plagued with undesirable attributes. One attempt comprised simply attaching a single line answering machine to each line. While this solution is clearly the most obvious, it is expensive due to the added cost of having to purchase two answering machines both of which include a power supply, control electronics, plastic housing, packaging, shipping and other costs associated with such a product. Furthermore, a party in receipt of messages on both answering machines must, if dialing in from a remote location, make two separate phone calls. Such a scenario is undesirable as it is time consuming and, should there be a need for a toll call, is generally twice as expensive.
Another proposed solution is a machine configured with a single recorder to accept and record a call from either line. However, this proposed solution, while less expensive then the previously discussed attempt, also has numerous drawbacks. For example, such a system is able to only record one call at a time. Thus, in a scenario in which two parties are calling at the same time, only the first arriving call can be recorded. The second but overlapping call does not have access to the answering machine. This proposed solution is obviously undesirable as it only allows one call to be recorded at a time. A further disadvantage of this proposed solution is that during the time the call recipient is remotely checking his messages, the automatic answering device is occupied in playback mode and hence unavailable to record an incoming call on either line. Similarly, if a caller is recording a message, the answering machine is not available to provide remote message retrieval.
The previously discussed need for an audio recording device for multiple telephone lines is likewise applicable to applications beyond audio data. For example, a similar need may arise in relation to automatic call answering and recording capability for video telephones. Video telephones not only provide audible information, but also a real time video image of the calling party.
Another area in which a need for such a device may arise is in relation to automatic video and/or audio recording devices, such as, for example, electronic surveillance devices and security video cameras. It is desirable to be able to record multiple streams of data from security cameras, both independently and simultaneously, using a system with minimal cost and complexity.
Accordingly, one object of the subject invention is to provide a method and apparatus for automatic signal acceptance and recording of data from multiple lines during times when data is being received over one or more of the lines simultaneously or concurrently.
A further object of the subject invention is to a provide a method and apparatus for providing remote signal retrieval capability while maintaining incoming signal recording capability.
Yet another object of the subject invention is provide a method and apparatus for recording multiple incoming data streams simultaneously or concurrently while avoiding undue increases in cost and complexity.
Yet another object of the subject invention is to reduce the memory and processing requirements of a multiple line telephone answering machine while still providing a capability for simultaneously or concurrently answering and recording multiple incoming calls.
Yet another object of the subject invention is provide a multiple line automatic answering machine capable of recording multiple incoming calls from a video phone.
A further object of the subject invention is to overcome the disadvantages of the prior art.
Further objects of the subject invention include utilization or achievement of the foregoing objects, alone or in combination. Additional objects and advantages will be set forth in description which follows, or will be apparent to those of ordinary skill in the art who practice the invention.
The subject invention provides a recording device and related method of operation for receiving and recording two or more simultaneously or concurrently arriving data inputs, in the form of audio signals, and the like, while minimizing the memory and processor requirements of the device. Minimizing these aspects advantageously reduces the cost and complexity of the recording device. In one embodiment, the invention comprises a dual line telephone answering device having capability to receive and simultaneously or concurrently record two incoming calls. Included in the answering device are one or more multiplexers configured to route the incoming signal to a selected one of a plurality of encoders. Each of plurality of the encoders performs signal compression on an incoming signal to reduce the amount of memory required for storage of the signal.
The multiplexers are configured to route the first arriving message to an encoder configured to encode the signal using a high-compression algorithm. A high compression of algorithm is advantageous since it requires only moderate computational resources while achieving significant compression ratios. A second signal, should it arrive concurrently with or during receipt of the first message, is routed to an encoder configured to encode the signal using a low-compression algorithm. This type of algorithm has the advantage of requiring only minimal computational resources and cost while achieving moderate compression ratios. After encoding, a memory manager stores the compressed signal in a memory.
Also included are means to detect the completion of the first incoming message, and a decoder capable of decompressing the second arriving message in preparation for re-encoding it by the high-compression encoder. Such a means allows reallocation of resources once encoding of the first arriving message has been completed, and redeployment of these resources to increase the compression ratio of the second arriving message. This desirably reduces the memory requirements of the answering device by reducing the amount of memory required to store the second arriving message without increasing the complexity of the processing circuitry.
The principles of the subject invention are equally applicable to a recording device for a video phone, in which the incoming signal comprises a video and audio feed. In this case, the memory storage requirements are even more significant because of the volume of data needed to represent a video image. Hence, the reduction in processing requirements and memory storage requirements available through incorporation of the subject invention, becomes even more significant.
It is contemplated that the subject invention will find application in various applications and environments other than answering machines and video phones. One such application comprises a recording device in a motion, voice, or sound activated surveillance system in which it is desired to record two or more data feeds simultaneously.